How do industries pollute water? Suggest any four measures to control water pollution.(Delhi - 2013)
Answers
Industries pollute water by discharging organic and inorganic industrial waste and affluent into water like paper, pulp, chemical, textile, etc into water bodies.
Some measures to control water pollution are:-
1. Over drawing of groundwater by some community should be regulated legally.
2 Careful recycle and reuse of the water in two or more successive stages.
3. Harvesting of rainwater to meet water requirements.
4. Treating hot water and effluents before releasing them in rivers and ponds. This can be done in three phases:
(i) Primary treatment by mechanical means (screening, grinding flocculation and sedimentation)
(ii) Secondary treatment by biological process
(iii) Tertiary treatment by physical chemical and biological processes (recycling of waste water).